Modules and exercises can easily be reordered in CloudFit.
To select the exercise you'd like to move, press and hold with either your finger or left mouse button if you're using the web app. The exercise will become movable as indicated by border.
You can then move the exercise up or down. When you are happy with the order, release your finger to place the exercise into its new position.
You can also reorder Modules using the same method.